Technical Abstract:
Internal Heat Necrosis Resistant Potato Clones Have Higher Tuber Concentrations of Magnesium, Sulfur, Manganese, and Calcium, and Lower Tuber Concentrations of Potassium than Susceptible Clones in the mid-Atlantic States. Sterrett, S.B.*, G.C. Yencho, M.R. Henninger, and K.G. Haynes. Eastern Shore AREC, VA Tech, Painter, VA 23420; Vernon James AREC, NCSU, Plymouth, NC 27962; Rutgers University, New Brunswick, NJ 08903; USDA/ARS, Beltsville, MD 20705
Internal heat necrosis (IHN) is a physiological disorder that results in necrotic tissue forming in the pith of potato tubers. Low levels of tuber calcium are thought to play a role in susceptibility to IHN. Studies were conducted in VA, NC, and NJ in 2001 and 2002 to determine the influence of soil-applied calcium on the expression of IHN and on tuber calcium concentration. Interspecific 4x-2x S. tuberosum x S. phureja-S. stenotomum hybrids, previously identified as resistant or susceptible to IHN, were planted with and without calcium sulfate (448 kg ha-1 Ca) applied in furrow over the seed-pieces. Yield, size distribution, specific gravity (sg), susceptibility to IHN (% ihn), severity of IHN (hnrate), and tuber concentrations of S, P, K, Mg, Ca, Na, Zn, Mn, Fe, Cu, and Al were determined from all site-years. There were significant differences among the clones for yield, sg, % ihn, hnrate, P, and Mg at all six site-years; for S, K, and Zn at five site-years; and, for Mn and Ca at four site-years. In those site-years with significant differences among clones, the IHN resistant clones had significantly higher tuber concentrations of Mg, S, Mn, and Ca and lower concentrations of P than the susceptible clones. These results suggest that there may be factors in addition to Ca that are important in the expression of IHN.